Video compression is performed by exploiting a correlation between signals in the temporal and spatial domains. Using a process referred to as motion compensation, an image may be transmitted or stored by encoding a prediction error (or residue) signal, instead of the original signal. The use of motion compensation introduces dependencies among the encoded frames (i.e., the quality of the reference frame affects the quality of the reconstructed frames). Conventional video coding systems do not explore such dependencies fully, especially if the video sequence is encoded in a single encoding pass.
Conventional video coding systems perform compression in a localized manner. Specifically, conventional systems attempt to achieve optimized compression quality for individual frames with little or no consideration about the variation of visual quality as a function of time and quality dependencies between different regions of the reconstructed video in neighboring frames.
It would be desirable to have a method and/or apparatus that incorporates the dependencies introduced by motion compensation and other forms of prediction into the parameter setting and mode selection process of video encoding.